Time-Resolved Fluorescence Anisotropy and Molecular Dynamics Analysis of a Novel GFP Homo-FRET Dimer
| Autor: | Jakub Nedbal, Andrew J. Beavil, Rebecca L. Beavil, Carla Molteni, Klaus Suhling, Alix Le Marois, Yurema Teijeiro-Gonzalez, Alessandro Crnjar |
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| Rok vydání: | 2020 |
| Předmět: |
Physics
0303 health sciences Green Fluorescent Proteins Biophysics Fluorescence Polarization Articles Molecular Dynamics Simulation Molecular physics Fluorescence Fluorescence spectroscopy 03 medical and health sciences Molecular dynamics 0302 clinical medicine Förster resonance energy transfer Microscopy Fluorescence Fluorescence Resonance Energy Transfer Time-resolved spectroscopy Exponential decay Anisotropy 030217 neurology & neurosurgery Fluorescence anisotropy 030304 developmental biology |
| Zdroj: | Biophysical Journal |
| ISSN: | 1542-0086 |
| Popis: | Forster resonance energy transfer (FRET) is a powerful tool to investigate the interaction between proteins in living cells. Fluorescence proteins, such as the green fluorescent protein (GFP) and its derivatives, are coexpressed in cells linked to proteins of interest. Time-resolved fluorescence anisotropy is a popular tool to study homo-FRET of fluorescent proteins as an indicator of dimerization, in which its signature consists of a very short component at the beginning of the anisotropy decay. In this work, we present an approach to study GFP homo-FRET via a combination of time-resolved fluorescence anisotropy, the stretched exponential decay model, and molecular dynamics simulations. We characterize a new, to our knowledge, FRET standard formed by two enhanced GFPs (eGFPs) and a flexible linker of 15 aminoacids (eGFP15eGFP) with this protocol, which is validated by using an eGFP monomer as a reference. An excellent agreement is found between the FRET efficiency calculated from the fit of the eGFP15eGFP fluorescence anisotropy decays with a stretched exponential decay model ( 〈 E F R E T e x p 〉 = 0.25 ± 0.05) and those calculated from the molecular dynamics simulations ( 〈 E F R E T M D 〉 = 0.18 ± 0.14). The relative dipole orientation between the GFPs is best described by the orientation factors 〈 κ 2 〉 = 0.17 ± 0.16 and 〈 | κ | 〉 = 0.35 ± 0.20, contextualized within a static framework in which the linker hinders the free rotation of the fluorophores and excludes certain configurations. The combination of time- and polarization-resolved fluorescence spectroscopy with molecular dynamics simulations is shown to be a powerful tool for the study and interpretation of homo-FRET. |
| Databáze: | OpenAIRE |
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